Process for producing aerated frozen products

ABSTRACT

A process for the production of a aerated frozen products by preparing a mixture of ingredients suitable for a frozen aerated product, adding an emulsifier mixture, aerating the mix to obtain an aerated mix having an overrun of about 20% to about 250%, and about 5% to about 100% for the frozen aerated ice cream and water ice, respectively, and freezing the aerated mix to produce the aerated ice cream or water ice.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of provisional application No.60/144,828 filed Jul. 21, 1999, the content of which is expresslyincorporated herein by reference thereto.

FIELD OF THE INVENTION

The present invention is directed to an aerated frozen products,including, but not limited to, ice cream, water ice, frozen yogurt,etc., and the methods for preparing the aerated frozen products.

BACKGROUND OF THE INVENTION

Traditionally, molded aerated frozen bars, ice cream, or water ice aremanufactured by partially freezing an ice cream mix, ice milk mix,frozen yogurt mix, water ice mix, or fruit juice mix in conventionalbatch or continuous freezers followed by pumping and filling the mixinto molds of different shapes and sizes. During the last decade, a newgeneration of freezers has been developed which are equipped withpre-whippers that enable the mix to be pre-aerated before beingpartially frozen in the freezer. The molded products are usuallyquiescently frozen using a cold brine system at −30° C. to −40° C. Ifdesired, after demolding, the molded products may be coated withchocolate or compound coating. Finally, the products are usuallypackaged and stored at about −30° C. until transport and distribution.

This traditional process for manufacturing molded aerated frozen bars,ice milk, yogurt, ice cream, or water ice has limitations. For example,the partial freezing of the mix in the freezer, followed by quiescentfreezing in the molds, leads to the formation of an icy texture, loss ofair, and formation of large air cells in the product having a size rangeof about 110-185 microns (Arbuckle, W. S. Ice Cream, Fourth Edition,1986, Van Nostrand Reinhold, New York, p 234). Shrinkage of the productsis often a problem and when eating the product, a very cold feeling inthe mouth is experienced. Furthermore, it is difficult to achieve morethan 20% overrun in water ice, a typical overrun is from 0% to 20% andusually is about 5%. It is very difficult to achieve more than 80%overrun and almost impossible to achieve an overrun of 120% or higher infinished ice cream products using conventional manufacturing.

Non molded products have similar problems. Air cells and ice crystalsstart growing immediately after production of non molded products.Significant air cell and ice crystal growth occurs duringtransportation, storage at the grocery store or during transportationand storage of the products by the consumer. None of the available nonmolded ice cream or water ice products inhibit or delay air cell or icecrystal growth after production or during hardening, transportation, ordistribution.

Currently, there is no process that can produce very stable finelyaerated frozen ice cream, ice milk, yogurt, or water ice having anaverage air cell size of less than 50 microns and an average ice crystalsize of 25 microns or that are heat shock resistant for a period of timeafter production. Thus, there is a need for finely aerated ice cream,ice milk, yogurt or water ice that maintain a smooth texture, do notsuffer from shrinkage, do not give a very cold feeling in the mouth,have an uniform appearance without large air pockets on the surface andhave a significantly higher heat shock resistance. Moreover, no processcan produce a stable overrun of more than 20% to about 100% for waterice products or an overrun between about 20% to about 250% for ice creamproducts. The present invention provides products and processes whichovercome these disadvantages.

SUMMARY OF THE INVENTION

The present invention relates to a process for the production of aeratedfrozen products comprising the steps of preparing a mixture ofingredients suitable for preparing a aerated frozen product, adding anemulsifier or mixture thereof in a suitable amount to obtain a mix,aerating the mix to obtain an aerated mix having an overrun of about 20%to about 250% for ice cream products and an overrun of about 5% to about100% for water ice products, and freezing the aerated mix to form theaerated frozen product. In this process, the mix can be an ice creammix, a water ice mix, a fruit juice mix, a frozen yogurt mix, a sherbetmix, or a mixture thereof.

The emulsifier mixture comprises at least one emulsifier capable offacilitating the formation and stabilization of fat α-crystals andpresent in an amount of about 0.01% to about 3% by weight of the mix.The emulsifier can be at least one of propylene glycol monostearate,sorbitan tristearate, lactylated monoglycerides, acetylatedmonoglycerides, or unsaturated monoglycerides, preferably the emulsifiermixture comprises propylene glycol monostearate, sorbitan tristearate,and unsaturated monoglycerides.

The mix of ingredients is typically prepared using conventional methodssuch as by combining the ingredients with shear mixing to disperse andsolubilize them into a homogeneous mass, followed by homogenizing themass and pasteurizing the homogenized mass. The homogenizing step can beconducted in a two stage homogenizer at a pressure of about 70 bar toabout 250 bar in the first stage and of about 0 bar to about 50 bar inthe second stage. Also, the mix can be aged after pasteurization bystoring at a temperature of about 0° C. to about 6° C. for about 1 hourto about 24 hours. If desired, the mix can be colored and flavoredbefore being aerated at a temperature of about 0° C. to about 12° C. toobtain the desired overrun. Preferably, the aerated mix is directly fedto a container or mold and frozen to produce the aerated frozen product,with the freezing being allowed to take place quiescently at atemperature of about −25° C. to about −45° C.

The aerating step can be conducted by allowing the mix pass through aconventional freezer at a temperature of about −4° C. to about −7° C. Incontrast, for molded products, the aerating step can be a whipping stepconducted by using a conventional mixer at a speed of about 150 rpm toabout 1000 rpm and at a flow rate of about 10 L/h to about 1000 L/h.

The invention also relates to an aerated frozen ice cream or water icewhich comprises a mixture of ingredients suitable for frozen aerated icecream or water ice and at least one emulsifier for facilitatingformation and stabilization of fat α-crystals.

The aerated frozen ice cream or water ice have an overrun of about 20%to about 250% and of about 5% to about 100%, respectively, and containair cells having an average size of less than about 50 microns whichcells are uniformly distributed throughout the ice cream or water iceand which are substantially invisible to the naked eye. Preferably, theaerated frozen products have air cells with an average size of about 15microns to about 40 microns and an ice crystal size of less than about30 microns. The process produces an aerated frozen product having asmooth texture similar to an extruded ice cream and heat shock resistantsuch that the apparent change in product volume after heat shocktreatment is less than about 5% by volume.

If desired, the aerated frozen products can contain inclusions or have acoating that optionally contains inclusions, which are added before orduring freezing. Further, the aerated frozen products may be in shelland core products with ice cream as a core and water ice, fruit juice,fruit ice, real fruit, or a mixture thereof as a shell or coating. Thelatter having an overrun of about 0% to about 20%.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings:

FIG. 1 illustrates ice crystals in a conventionally molded aerated icecream bar after heat shock.

FIG. 2 illustrates ice crystals in a molded aerated ice cream bar, madeby a process for producing frozen aerated ice cream, after heat shock.

FIG. 3 illustrates ice crystals of conventionally prepared ice creamsamples (standard) and ice cream samples of the present invention(test).

FIG. 4 illustrates ice crystals of heat shocked conventionally preparedsamples (standard) and samples of the present invention (test).

FIG. 5 illustrates a comparison of air bubble distribution ofconventionally prepared standard samples and samples prepared using thepresent invention before and after heat shock treatment.

DETAILED DESCRIPTION OF THE INVENTION

It has now been found that aerated frozen products mix can be finelyaerated in a freezer to a desired overrun by using an emulsifier blendfor bulk ice cream, bulk water ice, bulk yogurt, individual ice creamportions, cones, bars, etc. The emulsifier blend preferably contains amixture of propylene glycol monostearate, sorbitan tristearate, andunsaturated monoglycerides. This procedure eliminates the whipping stepof the prior art which either conducts a whipping step prior to freezingfollowed by molding, or partially freezes a mixture, followed bymolding. Neither process of the prior art provides a frozen ice cream,ice milk, yogurt, or water ice product that has a fine and stableaerated structure.

The emulsifier blend of the present invention facilitates and stabilizesfat α-crystals. Typically, in conventionally prepared frozen products,fat is present in a β-crystal structure. The fat β-crystal is anenergetically lower crystal structure and thus, a preferredconfiguration for fat crystals. The emulsifier blend of the presentinvention, however, facilitates the formation and stabilization of thehigher energy configuration fat α-crystals in the frozen aeratedproducts.

The presence of fat α-crystals in the aerated frozen products hasseveral advantages. The fat α-crystal configuration supports andstabilizes a fat film or structure surrounding the air cells whichprevents small air cells from agglomerating into larger air cells. Also,the surface areas of the fat α-crystals serve as barriers that do notallow ice crystals, within the aerated frozen products, to grow intolarger ice crystals. The formation of small air cells and theirstabilization through fat α-crystals substantially restricts the growthof ice crystals and this in turn, creates an aerated frozen product witha smoother, creamier texture and which is heat shock resistant.

Furthermore, the process of the present invention yields an ice creamproduct with an unconventionally high overrun of about 20% to about 250%and an unconventionally high overrun for water ice products of about 5%to about 100%. Moreover, the aerated frozen products have asignificantly higher resistance to shrinkage and heat shock, have asmoother uniform air pocket free appearance, and a creamier and moredesirable eating quality compared to conventionally prepared products.

The term “aerated frozen products,” as used herein, unless otherwiseindicated, means ice cream, water ice, yogurt, frozen yogurt, sherbert,fruit ice, low fat ice cream, ice milk, etc.

The term “heat shock,” as used herein, unless otherwise indicated, meansthe temperature fluctuations related to the storage and transportationof frozen ice cream, ice milk, yogurt, or water ice product. Heat shockcan be simulated by treating a frozen ice cream product to temperaturecycling of about −8° C. to about −20° C. every 12 hours, with 30 mintemperature ramp time for a period of about two weeks, or by any othermethod commonly used in the industry.

The mixture suitable for an aerated frozen product may be anyconventional mix such as an ice cream mix, a frozen yogurt mix, a waterice mix, a fruit juice mix, a sherbet mix, or a combination thereof withthe emulsifier blend used in the present invention. An ice cream mix maycontain fat, non-fat milk solids, carbohydrates, or stabilizers togetherwith water and, if desired, other conventional ingredients such asmineral salts, colorants, flavorings, inclusions, etc. A water ice mixcomprises fruit juices, sugar, stabilizer, and small amounts of milkfatand non-fat milk solids.

A typical aerated frozen product mix may contain fat in an amount ofabout 0.5% to about 18% by weight based on the total weight of the mix,non-fat milk solids in an amount of about 6% to about 15% by weightbased on the total weight of the mix, sugar in an amount of about 10% toabout 15% by weight based on the total weight of the mix, a sweetener inan amount of about 3% to about 8% by weight based on the total weight ofthe mix, an emulsifier blend in an amount of about 0.01% to about 3% byweight based on the total weight of the mix, and a stabilizer in anamount of about 0.1% to about 1% by weight based on the total weight ofthe mix.

The fat used may be a dairy fat, a non-dairy fat, or a mixture of both.When the fat is a dairy fat, it may be for instance, any milk fat sourcesuch as butter oil, butter, real cream, or a mixture thereof. When thefat is a non-dairy fat it may be, for instance, an edible oil or fat,preferably a vegetable oil such as coconut oil, palm kernel oil, palmoil, cotton oil, peanut oil, olive oil, soy bean oil, etc., or mixturesthereof.

The sugar used may be sucrose, glucose, fructose, lactose, dextrose,invert sugar either crystalline or liquid syrup form, or mixturesthereof.

The sweetener may be a corn sweetener in either a crystalline form ofrefined corn sugar (dextrose and fructose), a dried corn syrup (cornsyrup solids), a liquid corn syrup, a maltodextrin, glucose, or amixture thereof.

The emulsifier may be at least one emulsifier that facilitates formationand stabilization of fat α-crystals. The emulsifiers include but are notlimited to propylene glycol monostearate (“PGMS”), sorbitan tristearate(“STS”), lactylated monoglycerides, acetylated monoglycerides,unsaturated monoglycerides, including monoglycerides with oleic acid,linoleic acid, linolenic acid, or other commonly available higherunsaturated fatty acids. Preferably, the emulsifier blend comprises atleast one of PGMS, STS, or unsaturated monoglycerides. More preferablythe emulsifier blend comprises a combination of PGMS, STS, andunsaturated monoglycerides. The emulsifier blend should be present in anamount of about 0.01% to about 3%, preferably of about 0.1% to about 1%,and more preferably of about 0.2% to about 0.5% by weight of the mix.Preferably the emulsifier blend should be present in a combination ofPGMS, STS, and unsaturated monoglycerides. PGMS, STS, and unsaturatedmonoglycerides should be present in an amount of about 0.1% to about 1%,of about 0.01% to about 0.2%, and of about 0.01% to about 0.2% by weightof the mix, respectively. Preferably, PGMS, STS, and unsaturatedmonoglycerides should be present in an amount of about 0.2% to about0.5%, of about 0.02% to about 0.05%, and of about 0.02% to about 0.1% byweight of the mix, respectively. More preferably, the emulsifier blendshould be present in a combination of PGMS, STS, and unsaturatedmonoglycerides and in amounts of about 0.25% to about 0.35%, of about0.02% to about 0.03%, and of about 0.02% to about 35 0.05% by weight ofthe mix, respectively.

The stabilizer may be, for instance, a hydrocolloid such as agar,gelatin, gum acacia, guar gum, locust bean gum, gum tragacanth,carrageenan and its salts, carboxymethyl cellulose, sodium alginate orpropylene glycol alginate, or any mixture of hydrocolloids.

A typical process for the preparation of aerated frozen products can becarried out using conventional equipment. The first step comprisesmixing the ingredients under shear mixing to disperse and/or solubilizethe ingredients into a homogeneous mass. One of ordinary skill in theart with little or no experimentation can determine mixing time andconditions to obtain the desired homogeneous mass. Thereafter, thehomogeneous mass is preheated, e.g., to a temperature of about 62° C. toabout 75° C. The preheated homogeneous mass is conventionallyhomogenized, e.g., in a two stage homogenizer. The first stage isconducted at a pressure of about 70 bar to about 250 bar, preferably ofabout 100 bar to about 150 bar, more preferably about 150 bar. Thesecond stage is conducted at a pressure of about 0 bar to about 50 bar,preferably of about 20 bar to about 35 bar. Subsequently, pasteurizationof the homogenized mass is conducted under conditions commonly used inthe industry.

The pasteurization step is conducted at a temperature of about 50° C. toabout 100° C., preferably of about 60° C. to about 85° C. for a time ofabout 10 seconds to about 30 minutes, preferably for time of about 30seconds followed by cooling to a temperature of about 0° C. to about 10°C., preferably at a temperature of about 4° C. Preferably,pasteurization is conducted by either high temperature short time (HTST)or low temperature long time (LTLT) processing.

After pasteurization, the mix is preferably aged by allowing to stand ata temperature of about 0° C. to about 6° C., preferably of about 1° C.to about 5° C. and for a time of about 1 hour to about 24 hours,preferably of about 2 hours to about 18 hours and more preferably ofabout 4 hours to about 12 hours.

The mix is then colored and flavored as needed.

Subsequently, the mix is allowed to aerate in a conventional freezer forbulk, extruded, or cone products. If the mix is allowed to aerate in aconventional freezer, the draw temperature of the frozen aerated productshould be sufficient to generate a viscosity and shear in the freezerbarrel to create fine air cells of average mean diameter of 50 micronsor less after hardening of the aerated frozen product. Typically,drawing temperatures include about −4° C. to about −10° C., preferablyof about −5° C. to about 8° C.

If the mix is whipped using a conventional freezer, any freezer commonlyused in the industry can be used to whip the mixture, e.g. Hoyer, CBW,PMS, etc. The mix is normally pumped into the freezer at a temperatureof about 0° C. to about 8° C., preferably of about 2° C. to about 4° C.and substantially simultaneously an appropriate amount of air isintroduced into the mix. Depending upon overrun desired in the finalproduct a skilled artisan can easily determine the amount of airrequired. The step of freezing under agitation is conducted dependingupon the freezing point of the mix. Typically, the step is conducted ata temperature of about −4° C. to about −8° C., preferably of about −5°C. to about −6° C. The time required is dependent on the amount of mixand air, and the pumping flow rate. An artisan can easily determine thiswithout undue experimentation.

Subsequently, the aerated frozen product is packaged into bulkcontainers, extruded for bars or cones, or packaged into smallcontainers. Bulk containers include container sizes of 3 gallons to 0.5L, and small containers include container sizes of 250 ml to 50 ml.

The overrun for ice cream products aerated using a conventional freezeris in the range of about 20% to about 35 250%, preferably of about 40%to about 175%, more preferably of about 80% to about 150%. The overrunfor molded ice cream products aerated using a whipper is in the range ofabout 40% to about 200%, preferably of about 80% to about 150%. Theoverrun for aerated water ice is in the range of about 5% to about 100%,preferably of about 20% to about 60%.

The aerated mix is then fed, preferably directly, to a container, e.g.,by pumping through a filler, and then allowed to harden. Hardening maybe allowed to take place either by using blast freezers or nitrogentunnel at a temperature of about −30° C. to about −60° C. or quiescentlyat a temperature of about −25° C. to about −45° C., preferably of about−30° C. to about −40° C., or by other conventionally acceptable methods.

The aerated frozen products may afterwards be stored at a freezingtemperature, usually at a temperature in the range of about −25° C. toabout −35° C., preferably of about −28° C. to about −32° C., and morepreferably at about −30° C. If desired, the product can be repackagedbefore shipping. Also for individual sized portions the aerated frozenproducts may be coated, for instance with chocolate or a compoundcoating. Compound coatings include coatings which do not contain 100%cocoa fat and coatings that contain any vegetable oil, such as canolaoil, corn oil, soy oil, coconut oil, etc., or mixtures thereof. Thesecoatings may also contain inclusions such as nut pieces, fruit pieces,rice crisps, or other additives therein. Furthermore, the aerated frozenproduct may be placed between cookies, or other edible substrates toform ice cream sandwiches or the like. The final aerated frozen productsare then packaged and stored at a freezing temperature.

The aerated frozen products may include a shell rather than a coating.The shell material may include fruit juice, fruit ice, real fruit, waterice, or mixtures thereof. The shell may also have an overrun of about 0%to about 20%.

The aerated frozen product produced by the process of the presentinvention has a creamier and warm eating quality, and a smooth, uniform,homogeneous texture and appearance, with small air cells of an averagesize of less than about 50 microns uniformly distributed substantiallynone of which are visible to the naked eye. Preferably, the small aircells have an average size of about 15 microns to about 40 microns, andmore preferably of about 20 microns to about 35 microns. The aeratedfrozen products have an average ice crystal size less than ice crystalsin conventionally prepared ice cream or water ice before and after heatshock, improved heat shock resistance and improved shrinkage resistance.

The aerated frozen products of the present invention have an average aircell size of less than 50 microns and ice crystal size of about 25microns. The frozen aerated products of the present invention, afterheat shock subsequent to production, have an average air cell sizesimilar to the untreated product, an average ice crystal size belowabout 30 microns, and an apparent change in product volume of less thanabout 5% by volume. Also, the frozen aerated products can maintain asmoother and creamier texture and mouth feel, do not suffer fromshrinkage, and do not give a cold feeling in the mouth.

To summarize, the aerated frozen products produced by the process of thepresent invention have a texture which is smoother, creamier and have awarmer mouth feel than a conventionally ice cream or water ice even atlower overruns. The present invention also provides an aerated frozenice cream having an overrun of about 20% to about 250% and a water icehaving an overrun of about 5% to about 100% with small air cellsuniformly distributed and substantially none of which are visible to thenaked eye.

FIG. 1 illustrates the ice crystals of a conventionally prepared moldedaerated ice cream bar after heat shock, taken with a microscope at −20°C. The ice crystals are substantially larger and straighter in shape.

FIG. 2 illustrates the ice crystals of aerated frozen ice cream preparedas taught by the present invention taken with a microscope at −20° C.FIG. 2 shows that the ice crystals in products produced according to thepresent invention are thinner than ice crystals of conventionallyprepared frozen bars and of a substantially curved rod like shape.

FIG. 3 illustrates the ice crystals of a conventionally prepared icecream sample (standard) as compared to an ice cream sample made usingthe present invention. The standard ice cream sample clearly containsice crystals of larger size than the ice crystals of the ice creamsample using the present invention. Additionally, FIG. 4 demonstratesthat the standard ice cream sample after heat shock treatment containslarger ice crystals in comparison to the test sample prepared using thepresent invention.

The relationship shown in FIGS. 3 and 4 is graphically represented inFIG. 5 where air bubble distribution for both standard and test samples(samples prepared by the present process) is tabulated. The standardsample air cell size, represented by the accumulated area distribution,drastically increases after heat shock treatment, thus indicating severeair cell size growth. In contrast, the test sample accumulated areadistribution is unaffected by heat shock treatment. Consequently, afterheat shock treatment, the average ice crystal size in the test sampleremains constant while conventionally prepared ice cream undergoessignificant ice crystal growth.

EXAMPLES

The following Examples and accompanying drawings further illustrate thepresent invention.

Example 1

An ice cream mix was prepared from 8% (by weight) partially hydrogenatedpalm kernel oil, 11% nonfat milk solids, 12% sucrose, 6% corn syrupsolids (36DE) and 0.5% of a stabilizer blend containing combinations ofhydrocolloids such as guar, locust bean gum, carrageenan, carboxymethylcellulose, etc. together with emulsifiers. The ingredients were mixedwith agitation to disperse and solubilise them into a homogeneous mass,homogenized with a two stage homogenizer at 2000 psig pressure at thefirst stage and 500 psig pressure at the second stage, followed by HTSTpasteurization.

After pasteurization, the mix was aged by refrigerated storage at atemperature of 4° C. for 6 hours.

The aged mix was colored, flavored, and then aerated in an Oakes Mixerat a temperature of 4° C. to an overrun of 130%.

The aerated mix was pumped to a mold and allowed to freeze to give thefrozen molded bar. The freezing was allowed to take place quiescently ata temperature of −40° C. using cold brine. The frozen molded bar wasdemolded and subsequently coated with chocolate crunch bar at 35° C.,packaged, and stored at −30° C.

The frozen molded bar produced by the process of the present inventionhad a creamier and warm eating quality of an extruded product, a smooth,uniform, homogeneous texture and appearance, with small air cells of anaverage size of less than 50 microns uniformly distributed substantiallynone of which were visible to the naked eye. The molded aerated frozenbar had a quick melt with substantially no lingering of product in themouth. Ice crystals in the molded aerated frozen bar had a unique thinand substantially curved rod like shape and an average size of less thanice crystals in a conventionally molded aerated ice cream bar after heatshock, and had improved heat shock and shrinkage resistance.

Example 2

A water ice mix was prepared from 23% (by weight) sucrose, 7% corn syrupsolids (36 DE) and 0.6% stabilizer blend containing combinations ofhydrocolloids, such as guar, locust bean gum, pectin, carboxymethylcellulose, gelatin, microcrystalline cellulose, hydrolyzed soy or milkproteins, etc. with or without emulsifiers. The ingredients were mixedwith agitation to disperse and solubilise them into a homogeneous massin water, homogenized with a two stage homogenizer at 1500 psig pressureat the first stage and 500 psig pressure at the second stage, followedby HTST pasteurization.

After pasteurization, the mix was aged by refrigerated storage at atemperature of 4° C. for 6 hours.

The aged mix was colored, flavored, acidified (e.g. adding citric acidsolution), and then aerated in an Oakes Mixer at a temperature of 4° C.to an overrun of 100%.

The aerated mix was then pumped to a mold and then allowed to freeze togive the frozen molded bar. The freezing was allowed to take placequiescently at a temperature of −40° C. using cold brine. The frozenmolded bar was demolded, and then packaged and stored at −30° C.

The frozen molded bar produced by the process of the present inventionhad the creamier and warm eating quality of an extruded product, asmooth, uniform, homogeneous texture and appearance, with air cellssubstantially none of which were visible to the naked eye. The moldedaerated frozen bar had a quick melt with substantially no lingering ofproduct in the mouth.

Example 3

An ice cream was prepared using the ingredients described in Table Iusing a conventional freezer as a whipper. The ice cream product had anoverrun of 120%. The draw temperature at the freezer outlet was constantat −6° C. After whipping the ice cream in a freezer, the product wasplaced into containers, conventionally hardened, and stored at −30° C.

TABLE I Percent Composition Ingredients Conventional New Fat 10 10Non-fat milk solids 7.5 7.5 Whey solids 2.5 2.5 Sugar 12.5 12.5 Cornsyrup solids, 36 DE 4.5 4.5 Guar 0.15 0.15 CMC 0.05 0.05 Carrageenan0.02 0.02 Mono-diglycerides or monoglycerides 0.30 — Propylene glycolmonostearate — 0.3 Sorbitan tristearate — 0.03 Unsaturatedmonoglycerides — 0.05 Water 62.5 62.4 Total solids 37.5 37.6

To compare heat shock resistance, ice cream products made according tothe present invention and using conventional methods were tested. Bothtypes of ice cream products were treated to heat shock, as describedabove, or alternatively for 6 days at −8° C. Ice crystals, air bubblesize and sensory attributes of the products were evaluated before andafter the products were heat shock treated. Generally, the ice creamproducts using the present emulsifier system remained smoother andcomparable to fresh standard products. (Table II and FIGS. 3 and 4).Additionally, the ice crystals and air bubble growth of the productsaccording to the present invention were highly restricted during heatshock as compared to conventionally made ice cream products. (FIG. 5).

TABLE II Method of Sample Preparation Treatment Conventional Presentinvention Fresh/Not treated 6.6 8.1 Heat Shocked 4.7 8.3

Measured by a trained sensory panel using a smoothness scale of 0 to 10.0 being the least and 10 being the most smooth product.

What is claimed is:
 1. A process for the production of aerated frozenproducts comprising the steps of preparing a mixture of ingredientssuitable for preparing a frozen aerated product; adding an emulsifiermixture in a suitable amount to produce a mix; aerating the mix toobtain an aerated mix having an overrun of about 5% to about 250%; andfreezing the aerated mix to form an aerated frozen product; wherein theemulsifier mixture includes a blend of propylene glycol monostearate,sorbitan tristearate, and unsaturated monoglycerides so that theemulsifier mixture is capable of facilitating formation andstabilization of alpha fat crystals in an amount of about 0.1% to about3% by weight of the mix; and wherein the propylene glycol monostearateis present in an amount of about 0.1% to 1%, the sorbitan tristearate ispresent in an amount of about 0.01% to 0.2% and the unsaturatedmonoglycerides are present in an amount of about 0.01% to 0.2%, whereineach percent represents a weight percent based on the weight of the mix.2. The process according to claim 1, which further comprises selectingthe mix to be an ice cream mix, a water ice mix, a fruit juice mix, afrozen yogurt mix, a sherbet mix, ice milk mix, or a mixture thereof. 3.The process according to claim 1, wherein the mix of ingredients isprepared by combining the ingredients with shear mixing to disperse andsolubilize them into a homogeneous mass, followed by homogenizing themass and pasteurizing the homogenized mass.
 4. The process according toclaim 3, wherein the homogenizing step is conducted in a two stagehomogenizer at a pressure of about 70 bar to about 250 bar in the firststage and of 0 bar to about 50 bar in the second stage.
 5. The processaccording to claim 3, which further comprises aging the mix afterpasteurization by storing the mix at a temperature of about 0° C. toabout 6° C. for about 1 hour to about 24 hours.
 6. The process accordingto claim 1, which further comprises coloring and flavoring the mixbefore aerating in a mixer at a temperature of about 0° C. to about 12°C. to obtain the desired overrun.
 7. The process according to claim 1,wherein the aerated frozen product is water ice and the overrun is about5% to about 100%.
 8. The process according to claim 1, wherein thefrozen aerated product is ice cream and the overrun is about 20% toabout 250%.
 9. The process according to claim 1, wherein the aeratingstep is conducted by allowing the mixture to pass through a conventionalfreezer with a draw temperature of about −4° C. to about −7° C.
 10. Theprocess according to claim 1, wherein the aerating step is a whippingstep conducted by using a conventional mixer at a speed of about 10 L/hto about 1000 L/h.
 11. The process according to claim 1, wherein thewhipped mix is formed as individual serving portions, and those portionsare provided with a coating or shell.
 12. The process according to claim11 which further comprises providing inclusions in the coating or shell.13. The process according to claim 1, wherein the propylene glycolmonostearate is present in an amount of about 0.2% to 0.5%, the sorbitantristearate is present in an amount of about 0.02% to 0.05% and theunsaturated monoglycerides are present in an amount of about 0.02% to0.1%, wherein each percent represents a weight percent based on theweight of the mix.
 14. The process according to claim 1, wherein thepropylene glycol monostearate is present in an amount of about 0.25% to0.35%, the sorbitan tristearate is present in an amount of about 0.02%to 0.03% and the unsaturated monoglycerides are present in an amount ofabout 0.02% to 0.05%, wherein each percent represents a weight percentbased on the weight of the mix.
 15. The process according to claim 1wherein the emulsifier mixture is capable of facilitating formation andstabilization of alpha fat crystals in an amount of about 0.1% to about1% by weight of the mix.
 16. The process according to claim 1 whereinthe emulsifier mixture is capable of facilitating formation andstabilization of alpha fat crystals in an amount of about 0.02% to about0.05% by weight of the mix.
 17. The process according to claim 1 whereinthe aerated mix is packaged into a container prior to forming the frozenproduct.
 18. The process according to claim 1 wherein the aerated mix isfrozen in a freezer and then extruded into bars or cones.